A manufacturing process for a semiconductor device or LCD substrate includes forming a resist pattern on a substrate. Particularly, a resist pattern is formed on a substrate, for example a semiconductor wafer (hereinafter “wafer”), by forming a resist layer on the substrate, exposing the resist layer through a photomask, and developing the exposed wafer to obtain a desired pattern. Such process has been performed using an application and development device.
An application and development device includes a liquid processing unit, which contains an application unit to apply resist liquid, and an anti-reflection layer forming unit, which applies a reflection resistant chemical. Further, the device includes multiple application and anti-reflection layer forming units in order to achieve a high throughput.
As shown in FIG. 11, a liquid processing unit places a wafer W on a spin chuck 10, drops chemical liquid, such as resist liquid, from a nozzle 11 placed above spin chuck 10, and spin coats wafer W, spreading the chemical liquid diametrically using centrifugal force caused by rotating wafer W. During the spin coating, wafer W scatters a mist of liquid to an outside. Thus, a cup body 12 is provided around spin chuck 10, with an exhaustion passage 14 having a damper 13 is connected to the bottom of cup body 12. Accordingly, the atmosphere of cup body 12 is inhaled and exhausted through exhaustion passage 14.
The liquid processing unit performs spin coating, film drying, edge cutting (where a resist layer solvent is applied at the outer edge of wafer W to remove unnecessary resist layer), or drying. Each liquid processing unit has a high exhaust amount during spin coating, where the number of rotations is high, generating a large amount of mist. On the other hand, the exhaust amount is low during film drying, where the number of rotations is less than during spin coating in order to form a layer having a uniform thickness. The exhaust amount of the liquid processing unit is high again during edge cutting or drying, as the number of rotations is increased. In exhaustion passage 14, downstream of damper 13, the amount of exhaust is adjusted to equal a high exhaust amount. By controlling the opening of damper 13, a low amount of exhaust is channeled from upstream of damper 13. Thus, the exhaust amount can be controlled high and low.
Although the liquid processing unit controls the exhaust amount based on the type of processing, the unit usually sets the exhaust amount at high. Thus, the total exhaust amount of the application and development unit in which a plurality of liquid processing units is provided is (exhaust amount of one liquid processing unit)×(the number of liquid processing units). With reference to FIG. 11, the total exhaust amount is illustrated. Assume that there are three liquid processing units, and among them liquid processing unit 1A exhausts a high exhaust amount, while the other two liquid processing units 1B and 1C each have a low exhaust amount.
In the example, each liquid processing unit, 1A to 1C, emits a high exhaust amount (Eh) into exhaustion passage 14 downstream of damper 13. Damper 13 in liquid processing unit 1A is closed, and the upstream side of damper 13, that is to say, the inside of cup body 12, has a high exhaust amount Eh. Thus, when damper 13 is open external air enters liquid processing units 1B and 1C. Accordingly, the inside of cup body 12, upstream of damper 13, has a low exhaust amount E1. The amount of external air entering liquid processing units 1B and 1C is the difference between the high and low exhaust amounts (Eh−E1) making the exhaust amount for each liquid processing unit equal to the high exhaust amount Eh. Therefore, when there are three liquid processing units, the total exhaust amount E equals the sum of the three liquid processing units (E=3×Eh).
An inventor has proposed, as shown in Japanese Laid-Open Patent Publication No. 2006-229062, improving throughput by separating a block for applying a resist layer containing both a resist liquid application unit and an anti-reflection forming unit, and a block for development, independently forming transfer passages for wafers from a carrier block to an exposure device and from the exposure device to the carrier block. As shown in FIG. 12, multiple cup bodies 12, which are part of the liquid processing unit, can be arranged in parallel along the transfer passage. In this example, three (3) cup bodies 12 are arranged in parallel along the transfer passage. A common nozzle 15 is movably positioned along the transfer passage. Wafers placed in cup bodies 12 are sprayed with a resist liquid by moving and locating common nozzle 15 above each cup body 12.
Each exhaustion passage 14 is connected to the bottom of cup body 12. The atmosphere of each cup body 12 is inhaled and exhausted through a common passage 16 placed along the heat of cup body 12. As in FIG. 11, cup bodies 12 exhaust uniformly through exhaustion passage 14, downstream of damper 13, with high exhaust amount Eh. Also, when the exhaust amount of cup body 12 is the low exhaust amount E1, external air enters exhaustion passage 14 in the amount of (Eh−E1), in addition to the low exhaust amount E1 from upstream of damper 13, by controlling the opening of damper 13. Thus, a total exhaust amount E of liquid processing units can be calculated by (exhaust amount Eh of each cup body 12)×(the number of cup bodies).
This process requires multiple cup bodies for enhancing the throughput. However, an organic material may be included in the mist if the total exhaust amount of the liquid processing units is increased according to the number of cup bodies. Thus, the exhaust amount of the organic material and power consumption are increased, which is not desirable for reducing CO2 emission. Accordingly, it would be necessary to increase the number of arranged cup bodies without increasing the total exhaust amount.
Japanese Laid-Open Patent Publication No. 2006-229062 discloses exhausting the inside of a cup body at a set exhaust amount corresponding to the number of rotations of a substrate retainer. Accordingly, mist is prevented from attaching to the substrate, allowing a thin layer having uniform thickness to form. However, the exhaust amount is still controlled by the level of a damper, and the exhaust amount of downstream of the damper equals the high exhaust amount Eh. Thus, the total exhaust amount increases with an increased number of cup bodies. Accordingly, the stated drawbacks are not solved with this technology.